So I bought 08 335xi CPO(45k on it) a few months back, my first BMW, and have put about 2k miles on it. Have been reading up on it ever sence. Finally got around to changing my oil the other day, and have a few questions.

As an observation while I've been driving, I noticed the level was a little off the max, not a big deal or anything. Wasn't kicking codes out or anything like that. However, when I drained the oil, I only got a little over 5 qts out. There was a cup or so of oil left in the filter housing, but really not much.

I put 7 qts in, and the reading is now right at the max line as expected. I have to go back and check the paperwork on actaully when the oil was last changed by a dealership.

My question is, I think its unlikely, but is it possible it burnt through that much oil?

Or, which I think is more likely, durring the CPO process did BMW leave the oil at that level as it did not kick out any codes? I'm guessing they saw fit to leave about 5 qts in as that is an ok level to run on? And if they changed the oil, did they only put in 5 or so qts and not the required 7 qts?

Is there a possiblity that there was a qt still in the engine somewhere that didn't drain? I drove for about 15 min before I started, while I went to get the oil, as to let it heat up a bit.